.\" zip_set_file_compression.mdoc -- set compression method and its flags
.\" Copyright (C) 2012 Dieter Baron and Thomas Klausner
.\"
.\" This file is part of libzip, a library to manipulate ZIP files.
.\" The authors can be contacted at <libzip@nih.at>
.\"
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.Dd May 1, 2012
.Dt ZIP_SET_FILE_COMPRESSION 3
.Os
.Sh NAME
.Nm zip_set_file_compression
.Nd set compression method for file in zip
.Sh LIBRARY
libzip (-lzip)
.Sh SYNOPSIS
.In zip.h
.Ft int
.Fn zip_set_file_compression "struct zip *archive" "zip_uint64_t index" \
"zip_int32_t comp" "zip_uint32_t comp_flags"
.Sh DESCRIPTION
The
.Fn zip_set_file_compression
function sets the compression method for the file at position
.Ar index
in the zip archive to
.Ar comp
with the compression method specific
.Ar comp_flags .
The
.Ar comp
is the same as returned by
.Xr zip_stat 3 .
For the
.Ar comp
argument, currently only the following values are supported:
.Bl -tag -width ZIP_CM_DEFLATE_XX
.It Dv ZIP_CM_DEFAULT
default compression; currently the same as
.Dv ZIP_CM_DEFLATE .
.It Dv ZIP_CM_STORE
Store the file uncompressed.
.It Dv ZIP_CM_DEFLATE
Deflate the file with the
.Xr zlib 3
algorithm and default options
.El
.Pp
The
.Ar comp_flags
argument is currently ignored.
.\" For the comp_flags argument, the lower 4 bits define the compression
.\" level.
.\" 0 is fastest compression, 15 is highest compression
.\" .Dv ZIP_COMP_FL_DEFAULT
.\" can be used to specify that the default shall be used.
.\" Further compression method specific flags will be added over time.
.Pp
The current compression method for a file in a zip archive can be
determined using
.Xr zip_stat 3 .
.Sh RETURN VALUES
Upon successful completion 0 is returned.
Otherwise, \-1 is returned and the error information in
.Ar archive
is set to indicate the error.
.Sh ERRORS
.Fn zip_set_file_compression
fails if:
.Bl -tag -width Er
.It Bq Er ZIP_ER_INVAL
.Ar index
is not a valid file index in
.Ar archive ,
or the argument combination is invalid.
.It Bq Er ZIP_ER_COMPNOTSUPP
Unsupported compression method requested.
.It Bq Er ZIP_ER_RDONLY
Read-only zip file, no changes allowed.
.El
.Sh SEE ALSO
.Xr libzip 3 ,
.Xr zip_stat 3
.Sh AUTHORS
.An -nosplit
.An Dieter Baron Aq Mt dillo@nih.at
and
.An Thomas Klausner Aq Mt tk@giga.or.at
